Manufacture of dihalogen paraffins.



. No Drawing.

i I IN.

FRANCIS EDWARD MATTHEWS, OF BLACKHEATH, AND HENRY JAMES WHEELER BLISS, 01E STOCKWELL, LONDON, ENGLAND.

MANUFACTURE OEDIHALOGEN PARAFFIN S.

T 0 all whom it may concern Be it known that we, FRANCIS EDWARD MATTHEWS, Ph. D., F. I. (l, a subject of the King of the UnitedKingdom of Great Britain and Ireland, and residing at Ash Lawn, The Glebe, Blackheath, in the county of Kent, England, and HENRY JAMES WHEELER BLIss, M.'A., a subject of the United Kingdom of Great Britain and Ire-- land, and residing at Ingram House, Stockwell, in the county of London, England, have invented new and useful Improvements in the manufacture of Dihalogen Paraflins, of which the following is a specification.

The preparation of the dihalogen substitution derivatives of the paraflins having the halogen attached to different carbon atoms, is of considerable importance for the production of doubly unsaturated hydrocarbons and other products.

In obtaining dihalogen paraffins from the parafiins it has been proposed to prepare a monohalid, convert this to an olefin and add halogen to halid may be directly a dihalid. In either case, four atoms of halogen are required to convert one molecule of parafiin to one molecule of dihalid.

According to the present invention, the

production ofeach molecule of dihalid requires only two atoms of halogen.

We obtain a mixture of saturated and unsaturated hydrocarbons including olefins in any suitable manner, for example, by heating a saturated parafiin hydrocarbon with or without the aid of a catalyst. It is difficult and in some cases impossible to separate the saturated and unsaturated hydrocarbons by fractionation. Similarly the product which may be obtained by the halogenation of such a mixture contains a mixture of dihalids which are diflicult toseparate on account of the presence of other products, a. g. parafiins and a proportion of higher and lower halids of varying molecular weights, some of which may have boiling points approximating to those of the de sired dihalids. On the above account the cracked mixture thus obtained has hitherto not been considered suitable for many chem-- ical purposes. According to this invention we fractionate'such a mixture so that the olefins in each fraction are chiefly olefins Specification of Letters Patent.

with the same the latter or again the mono-' halogenated, yielding Patented Nov. a, 1915.

Application filed June 6, 1914. Serial No. 843,510.

number of. carbon atoms in the molecule, Vi e treat the fraction so obtained either in the liqnid condition, or in the condition of vapor, with halogen in suflicient quantity only to effect the saturation of the unsatue rated hydrocarbons present, the halogenation being preferably carried out in the dark and at a low temperature and with the hydrocarbon in a state of dilution in order to avoid substitution.

-l-n place of the halogen itself, or of part thereof, we may use a substance capable of yielding halogen, the halogen and the halogen-yielding substance being hereinafter collectively referred to .as halogenizing agents.

The progress of ed by adding a small quantity of bromin to a sample. The color of the bromin should persist for some time if sufficient halogen has already been added. [The mixture obtained by halogenation as aforesaid can easily be fractionated so as to separate the saturated hydrocarbons from the halids.

The following is an exampleof how this invention can be performed but it is not limited thereto: A mixture of parafiins, containing parafl'ins C H to C,,I-I is cracked by heating; for example by passing the vaporized mixture through a hottube or by placing in the vapor or in the liquid mixture a wire which is electrically heated. The process may be carried on with or Without the assistance of a catalyst, for example a metal such as nickel, and in the presence or not'of steam or other diluent. The product is then condensed. It contains a proportion of saturated and unsaturated hydrocarbons 0,11 to 0 H and (Ll-I to O I-I The condensed product is fractionated and the fraction containing unsaturated C, hydrocarbons (b. p. 30 to 40) and unsaturated C, hydrocarbons (b. p. 65 to 73) are collected separately. Lower and hi her fractions, if forms, may also be collected, or may be rejected-and used as solvents or for any pther purpose to which they are applicable The selected fractions are then treat-' ed with halogen as aforesaid, and fractionated to recover the dihalids, whlch may be used for any required purpose or be treated in any suitable manner, for example, ac-

the reaction may be test cording to the specification of the application for British Letters Patent No. 17234 A. D. 1912 to remove two molecular proportions of halogen acid, yielding doubly unsaturated hydrocarbons.

It is clear that in the above example the fractionation before halogenation may be in some cases carried out to narrower limits of temperature so that one isomeric olefin alone is present; more generally however it is preferable to carry out any further separation by fractionating the halids.

\Ve may also use other mixtures containing a proportion of unsaturated hydrocarbons and we do not limit ourselves to the hereinbefore described method of preparing an unsaturated mixture.

lertain mixtures may contain a proportion of doubly unsaturated hydrocarbons; for instance it is known that a proportion of butadiene is found in the gases produced by cracking. Such doubly unsaturated hydrocarbons may in some cases be recovered or separated for example by fractionation or polymerization or the halids may be recovered after halogenat ion has taken place. Similarly the halids of acetylenic hydrocarbons may be separated.

The residual gases, saturated hydrocarbons and fractions obtained in carrying out this invention may be any other purpose to which they are applicable or they may in some cases be treated again in accordance with this invention.

Having now particularly described and ascertained the nature of our said invention used for fuel or for I and in what manner the same is to be performed we declare that what We claim is 2- 1. Processof preparing dihalogen substitution derivatives of the paraffin hydrocarbons which consists in subjecting a mixture containing olefin hydrocarbons and saturated hydrocarbons to fractional distillation so that the olefin hydrocarbons in each fraction are chiefly olefin hydrocarbons having the same number of carbon atoms in the molecule, and then treating the fractions with only suflicient halogenizing agents to effect the saturation of the unsaturated hydrocarbons and subsequently separating the dihalids by fractional distillation, substantially as described.

The process of preparing dihalogen substitution derivatives of the parailin hydrocarbons,which consists in subjecting a mixture containing olefin hydrocarbons and saturated hydrocarbons to fractional distillation to obtain a fraction containing chiefly olefin hydrocarbons having the same number of carbon atoms in the molecule, and then treating said fraction with only sufiicient halogcnizing agent to elfect the saturation of the unsaturated. hydrocarbons, substantially as described.

In testimony whereof we have names to this specification in two subscribingwitnesses.

FRANCIS EDWARD MATTHEWS.

HENRY JAMES WHEELER BLlSS. \Vitnesses a O. J. VORTH,

W'. E. ROGERS.

signed our the presence of 

